The present invention relates generally to tufted nonwoven fibrous web materials. More particularly, it is concerned with new and improved tufted webs made by wet papermaking techniques and exhibiting the appearance and characteristics of high loft absorbent bath toweling and the like.
As is well known, conventional wet papermaking techniques have traditionally produced compact, closely formed sheets exhibiting the rattle and smooth surface characteristic usually associated with paper. In recent years, increased emphasis has been placed on the production of nonwoven fabrics for apparel, household and industrial uses. Such fabrics, though initially produced as dry fibrous batts processed on textile carding equipment, now include certain wet-laid webs made on papermaking machines using techniques especially developed for the production of nonwoven materials. The materials thus produced exhibit textile-like characteristics including softness, drape and hand, and have found extensive use in the field of disposable fabrics.
Many of the nonwoven fabrics produced heretofore have utilized a patterned configuration of one form or another in order to impart to the material the desirable characteristics of woven cloth. This patterned configuration has generally been achieved by subjecting a preformed web to controlled destructive forces which rearrange and reorient the fiber construction and provide a multitude of small apertures which improve the drape characteristics of the resultant nonwoven material. Typical examples of this fiber rearranging technique can be found in U.S. Pat. Nos. 2,862,251; 3,042,576; 3,081,515 and 3,485,706.
Another technique for imparting some of the characteristics of woven fabrics to nonwoven fibrous materials is the use of a needle punch operation that forms "pegs" of fibers which increase the structural integrity of the web while improving the flexibility and hand thereof. Still other techniques involve light surface brushing to provide a raised nappy surface exhibiting improved softness, as for example in U.S. Pat. No. 3,101,520, or the use of electrostatic fiber flocking to achieve a comparable nappy surface. A further technique involves the utilization of a crepe or loop-forming operation either alone or in combination with a needle punch. The nonwoven fabrics containing the looped fibers tend to imitate the looped configuration characteristics of woven terry cloth and reportedly exhibit improved softness and high loft.
In substantially all of the foregoing processes it is necessary to first form a web and then subject it to an additional structure altering treatment to provide the desired characteristics. Additionally, in many instances the initial nonwoven web materials are not produced in accordance with the more economical wet papermaking technique, thereby further adding to the cost of the finished product. Some progress has been made in producing patterned webs using a wet papermaking process and mention can be made of the dual wire technique disclosed in U.S. Pat. No. 3,322,617 and the techniques found in U.S. Pat. No. 2,940,891.
Despite these previous attempts, it was found that wet papermaking techniques had not been used successfully to produce tufted nonwoven toweling products having the loft, softness, bulk, absorbency and drape characteristics of turkish toweling. A key factor in the inability of the prior art techniques to produce such materials has been the inability of the wet process to provide high loft materials having a high concentration of absorbent relatively loose and flexible yet sturdy fibers extending outwardly from the main body of the web. However, a major step in that direction is described in our U.S. Pat. No. 3,834,983 issued Sept. 10, 1974 and entitled "Process of Forming Wet Laid Tufted Nonwoven Fibrous Web From a Viscous Fibrous Dispersion and Product". Described therein is a technique that provides tuft formation as the web is being formed. This is achieved using a viscous dispersing medium for the fibers and a coarse web forming wire screen. Although good tuft formation is obtained when using a screen of the type described, some entanglement of the free ends of adjacent tufts prior to removal of the web from the screen has been experienced. Such entanglement not only adversely affects the appearance of the product but also causes difficulty in removing the web from the web forming wire. These entanglement problems have been overcome by using the apertured plate described in our copending application Ser. No. 489,411, filed July 17, 1974.
Accordingly, it is an object of the present invention to provide an improvement in the product described in our aforementioned patent and more specifically to provide an improved high loft, tufty or tufted nonwoven fibrous web material exhibiting the softness, drape, hand, feel, bulk and absorbency associated with woven looped materials such as turkish or terry toweling.
Another object of the present invention is to provide a new and improved product which uniquely combines the advantageous features of the wet papermaking technology by having on at least one surface thereof a multiplicity of fiber tufts or bundles extending outwardly from the continuous planar body portion of the product in the form of multiple strand fiber bundles exhibiting the appearance of a serried or spirally consolidated fiber bundle or cluster that is twisted back on itself similar to a French knot.
Still another object of the present invention is to provide a technique and product of the type described wherein tufts are simultaneously formed on both sides of the web material during web formation.
Other objects will be in part obvious and in part pointed out in more detail hereinafter.
These and related objects are accomplished in accordance with the present invention by providing a fibrous nonwoven water-laid web material exhibiting high loft, bulk and absorbency. The web is comprised of a substantially planar web body portion of randomly arranged water dispersable fibers and a multitude of separate, spaced fiber tufts of high concentration arrayed on at least one surface thereof. The tufts are composed of a plurality of closely associated, relatively independent fibers having one end anchored within the web body portion and extending from the web body portion in the form of compressively resilient, spring-like fiber bundles exhibiting a twisted consolidated and serried configuration. The fibers within the tufts have free ends that are not anchored within the body but are twisted back on themselves in an intorted spiraled involution that imparts a nubby character to the surface yet retains the desired resiliency and loft.
A better understanding of the objects, advantages, features, properties and relationships of the invention will be obtained from the following detailed description and accompanying drawings which set forth an illustrative embodiment and are indicative of the way in which the principles of the invention are employed.